Hermetic compressor

ABSTRACT

Disclosed is a hermetic compressor capable of preventing an intake valve from making contact with a piston without reducing compressing efficiency of the compressor. The hermetic compressor includes a cylinder block having a compressing chamber, a piston performing a reciprocation, a cylinder block coupled at an side of the cylinder block so as to close the compressing chamber and an intake valve plate which is provided between the cylinder block and the cylinder head and has an intake valve which controls a flow of a refrigerant introduced into the compressing chamber, wherein a compressing surface of the piston facing the intake valve plate forms a flat surface parallel to the intake valve plate and an anti-contact portion which receives a part of the intake valve is formed on the compressing surface so as to prevent the piston from making contact with the intake valve during the reciprocation of the piston.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.2006-32423 filed on Apr. 10, 2006, in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hermetic compressor, and moreparticularly to a hermetic compressor capable of preventing an intakevalve from making contact with a piston without reducing the compressingefficiency of the compressor.

2. Description of the Prior Art

A hermetic compressor has been widely used in a refrigerating cycle fora refrigerator or an air conditioner. Such a hermetic compressorincludes a closed casing forming an external appearance, a compressingunit which is provided in the closed casing to compress refrigerant anda driving unit which provides the compressing unit with driving force.

Among these components, the compressing unit includes a cylinder blockforming a compressing chamber in which the refrigerant is compressed, apiston performing a linear reciprocation in the compressing chamber soas to compress the refrigerant, a cylinder head coupled to one side ofthe cylinder block so as to close the compressing chamber and providedwith an intake chamber and an exhaust chamber that are separated fromeach other, and a valve unit which is provided between the cylinderblock and the cylinder head so as to control the flow of the refrigerantwhich is introduced into the compressing chamber from the intake chamberor is exhausted from the compressing chamber into an exhaust chamber.

Under this configuration, if the driving unit is operated, the pistonperforms the linear reciprocation in the compressing chamber so that therefrigerant provided at an outer portion of the closed casing isintroduced into the intake chamber of the cylinder head, and then istransferred to the compressing chamber so that the refrigerant iscompressed in the compressing chamber. In this manner, the refrigerantcompressed in the compressing chamber is exhausted into the exhaustchamber of the cylinder head and then is exhausted out of the closedcasing through an exhaust tube. Such a process is repeated, so that therefrigerant is compressed by means of the compressor.

The valve unit includes a valve plate having an intake hole and anexhaust hole through which the compressing chamber is communicated withthe intake chamber and the exhaust chamber, an intake valve whichopens/closes the intake hole and an exhaust valve assembly whichopens/closes the exhaust hole.

the intake valve is designed to be easily opened according to themovement of the piston during an intake process of such a hermeticcompressor. In order to allow the intake valve to be easily opened, theintake valve is designed to be easily bent according to pressurevariation in the compressing chamber.

Since the intake valve is designed to be easily bent according to thepressure variation in the compressing chamber, if the intake vlave isexcessively bent relative to the moving distance of the piston when thepiston moves from the top dead point to the bottom dead point, theintake valve makes contact with a surface of the piston. If the intakevalve makes contact with the piston, the intake valve or the piston maybe broken, degrading the reliability of the product. In addition, ifdebris derived from the breakage remains in the compressing chamber, thecylinder block may be worn.

In this manner, in order to prevent the intake valve from making contactwith the piston, a gasket having a large thickness is interposed betweenthe piston and the intake valve. However, if the thickness of the gasketis too large, a dead volume is increased between the piston and theintake valve, degrading the compressing efficiency of the compressor.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above-mentionedproblems occurring in the prior art, and an object of the presentinvention is to provide a hermetic compressor capable of preventing anintake valve from making contact with a piston without reducing thecompressing efficiency of the compressor.

In order to accomplish the above object, according to an aspect of thepresent invention, there is provided a hermetic compressor comprising acylinder block having a compressing chamber, a piston performing areciprocation in the compressing chamber, a cylinder head which iscoupled to one side of the cylinder block so as to close the compressingchamber and an intake valve plate having an intake valve which isprovided between the cylinder block and the cylinder head so as tocontrol a flow of a refrigerant which is introduced into the compressingchamber, wherein a compressing surface of the piston facing the intakevalve plate forms a flat surface parallel to the intake valve plate, andan anti-contact portion which receives a part of the intake valve isformed on the compressing surface so as to prevent the piston frommaking contact with the intake valve during the reciprocation of thepiston.

The anti-contact portion includes a recess having a shape correspondingto a shape of the intake valve.

The anti-contact portion has a width larger than a width of the intakevalve so that the intake valve passes through the anti-contact portion.

The intake valve is formed by cutting the intake valve plate, in whichone end of the intake valve serves as a fixing end and the other end ofthe intake valve serves as a free end.

A depth of the anti-contact portion gradually increases from the fixingend to the free end.

A volume of the anti-contact portion is set within a predetermined rangewhich does not reduce a compressing efficiency of the hermeticcompressor.

A volume of the anti-contact portion is set within a predetermined rangewhich does not reduce a compressing efficiency of the hermeticcompressor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view representing a hermetic compressoraccording to an embodiment of the present invention;

FIG. 2 is an exploded perspective view representing a valve unit and apiston shown in FIG. 1;

FIG. 3 is a sectional view representing a piston when the piston shownin FIG. 2 reaches a top dead point; and

FIG. 4 is a sectional view representing an operation of an intake valvewhen the piston moves back from the top dead point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a hermetic compressor according to a preferred embodimentof the present invention will be explained in detail with reference tothe accompanying drawings.

A hermetic compressor according to an embodiment of the presentinvention is as shown in FIG. 1 includes a closed casing 1 in which atop casing 1 a and a bottom casing 1 b are coupled with each other, acompressing unit 10 which is provided in the closed casing 1 to compressrefrigerant and a driving unit 20 which provides the compressing unit 10with driving force. An intake tube 2 which guides the refrigerant froman exterior into the closed casing 1 is provided at one side of theclosed casing 1 and an exhaust tube 3 which exhausts the compressedrefrigerant in the compressed unit 10 into the outside of the closedcasing 1 is provided at the other side of the closed casing 1.

Among these components, the compressing unit 10 includes a cylinderblock 11 which has a compressing chamber 11 a for compressing therefrigerant, a piston 12 which compresses the refrigerant whileperforming a linear reciprocation in the compressing chamber 11 a, acylinder head 13 which is coupled to one side of the cylinder block 11to close the compressing chamber 11 a and has an intake chamber 13 aandan exhaust chamber 13 b that are separated from each other, and a valveunit 30 which is provided between the cylinder block 11 and the cylinderhead 13 and controls a flow of the refrigerant which is introduced intothe compressing chamber 11 a from the intake chamber 13 a, or isexhausted from the compressing chamber 11 a into the exhaust room 13 b.

the driving unit 20 provides a driving force to allow the piston 12 toreciprocate in the compressing chamber 11 a, and includes a stator 21fixed in the closed casing 1 and a rotor 22 which is spaced apart fromthe stator 21 so as to electro-magnetically interact with the stator 21.A rotating shaft 23 is provided on the center portion of the rotor 22such that the rotating shaft 23 can rotate together with the rotor 22.Provided below the rotating shaft 23 are an eccentric portion 24, whichis eccentrically rotated, and a connecting rod 25. In order to convertthe eccentric movement of the eccentric portion 24 connecting rod 25. Inorder to convert the eccentric movement of the eccentric portion 24 intothe linear movement, one end of the connecting rod 25 is rotatablycoupled to the eccentric portion 24 and the other end of the connectingrod 25 is coupled to the piston 12 such that the connecting rod 25 canperform the linear and rotating movement.

When a power is applied to the hermetic compressor, the rotating shaft23 is rotated according to an electromagnetic interaction between thestator 21 and the rotor 22, and the piston 12 which is connected withthe eccentric portion 24 by means of the connecting rod 25 performs thelinear reciprocation in the compressing chamber 11 a. Through thisprocess, the refrigerant remaining at the outside of the closed casing 1is introduced into the intake chamber 13 aof the cylinder head 13through the intake tube 2 and then is transferred to the compressingchamber 11 a so as to be compressed in the compressing chamber 11 a. Inthis manner, the refrigerant compressed in the compressing chamber 11 ais exhausted into the exhaust chamber 13 b of the cylinder head 13 andis exhausted out of the closed casing 1 through an exhaust tube 4.

Meanwhile, a valve unit 30 includes a valve plate 40 which has an intakehole 41 and an exhaust hole (not shown) through which the compressingchamber 11 a of the cylinder block 11 communicates with the intakechamber 13 a and the exhaust chamber 13 b of the cylinder 13. Further,an intake valve plate 35 having an intake valve 31, which opens/closesthe intake hole 41, is assembled to one side surface of the valve plate40 facing the cylinder block 11 and an exhaust valve assembly 50, whichopens/closes the exhaust hole, is assembled to the other side surface ofthe valve plate 40 facing the cylinder head 13.

For reference, reference numerals 32 and 33 represent gaskets which areinterposed between the cylinder head 13 and the valve plate 40, andbetween the cylinder block 11 and the intake valve plate 35,respectively. Bolt coupling holes are formed at outer peripheralportions of the gaskets, 32 and 33, the valve plate 40, and the cylinderhead 13, respectively. Such a valve unit 30 is installed between thecylinder block 11 and the cylinder head 13 by means of a fixing bolt 34,which is screw-coupled into the bolt coupling hole from the outside thecylinder head 13 so as to be coupled with the cylinder block 11.

A peripheral portion of the intake valve 31, except for an end portionthereof, is cut from the intake valve plate 35 so that the intake valve31 is integrally formed with the intake valve plate 35. At this time,one end portion of the intake valve 31 serves as a fixing end 31 a fixedto the intake plate 35 and the tip portion of the intake valve 31 servesas a free end 31 b, which is elastically deformed so as to open or closethe intake hole 41.

Meanwhile, the piston 12, which is guided by the cylinder block 11 whilemoving in forward and backward directions, has a cylindrical shape and acompressing surface 12 a of the piston 12 facing the intake valve plate35 forms a flat surface which is parallel to the intake valve plate 35.Further, the compressing surface 12 a has an anti-contact portion 60 soas to prevent the compressing surface 12 a from making contact with theintake valve 31 during the reciprocation of the piston 12.

The anti-contact portion 60 is a recess having a shape corresponding tothe shape of the intake valve 31 and the volume of the anti-contactportion 60 is set within a range which does not reduce the compressingefficiency of the hermetic compressor. In addition, the anti-contactportion 60 has a width larger than a width of the intake valve 31, sothat the intake valve 31 can pass through the anti-contact portion 60when the free end 31 b of the intake valve 31 is bent to be received inthe anti-contact portion 60.

In addition, since the free end 31 b of the intake valve 31 is rotatedabout the fixing end 31 a, the depth of the anti-contact portion 60 isgradually increased from the fixing end 31 a to the free end 31 b.

Hereinafter, the operation and functions of the hermetic compressoraccording to the exemplary embodiment of the present invention will beexplained with reference to FIGS. 3 and 4.

FIG. 3 is a view representing a piston when the piston moves forward tothe maximum extent so as to reach a top dead point. At this time,pressure is applied in a direction in which the piston 12 pushes theintake valve 31, so that the intake valve 31 does not open the intakehole 41.

FIG. 4 is a view representing positions of the piston 12 and the intakevalve 31 when the piston 12 moves back from the top dead point to thebottom dead point. If the piston 12 reaches the top dead point and movesback to the bottom dead point, negative pressure is applied to an insideof the compressing chamber 11 a, so that the free end 31 b of the intakevalve 31 is bent toward the inside of the compressing chamber 11 a aboutthe fixing end 31 a.

In this case, the anti-contact portion 60, which can receive the freeend 31 b of the intake valve 31, is formed on the compressing surface 12a of the piston 12 so as to prevent the intake valve 31 from makingcontact with the piston 12.

As described above, the hermetic compressor according to the presentinvention can prevent the components from being damaged by preventingthe intake valve from making contact with the piston, and can preventthe cylinder block from being worn by preventing debris derived from thebreakage of the components from being introduced into the compressingchamber.

In addition, since the recess having a minimum volume is formed in thecompressing surface of the piston, the distance between the piston andthe intake valve plate can be reduced, so that the compressingefficiency of the compressor can be prevented from being degraded.

1. A hermetic compressor comprising: a cylinder block having acompressing chamber; a piston performing a reciprocation in thecompressing chamber; a cylinder head which is coupled to one side of thecylinder block so as to close the compressing chamber; and an intakevalve plate having an intake valve which is provided between thecylinder block and the cylinder head so as to control a flow of arefrigerant which is introduced into the compressing chamber, wherein acompressing surface of the piston facing the intake valve plate forms aflat surface parallel to the intake valve plate, and an anti-contactportion which receives a part of the intake valve is formed on thecompressing surface so as to prevent the piston from making contact withthe intake valve during the reciprocation of the piston.
 2. The hermeticcompressor as claimed in claim 1, wherein the anti-contact portionincludes a recess having a shape corresponding to a shape of the intakevalve.
 3. The hermetic compressor as claimed in claim 2, wherein theanti-contact portion has a width larger than a width of the intake valveso that the intake valve passes through the anti-contact portion.
 4. Thehermetic compressor as claimed in claim 2, wherein the intake valve isformed by cutting the intake valve plate, in which one end of the intakevalve serves as a fixing end and the other end of the intake valveserves as a free end.
 5. The hermetic compressor as claimed in claim 4,wherein a depth of the anti-contact portion gradually increases from thefixing end to the free end.
 6. The hermetic compressor as claimed inclaim 2, wherein a volume of the anti-contact portion is set within apredetermined range which does not reduce a compressing efficiency ofthe hermetic compressor.